Microsoft CEO Steve Ballmer will demonstrate tablet computers running a version of Windows 7, including a Samsung model with a slide-out keyboard, at the 2011 Consumer Electronics Show in January, The New York Times reported yesterday in a blog post.

The Times didn't name its source, but the person described the Samsung slate device as "similar in size and shape" to the Apple iPad, but "not as thin." The slide-out keyboard is said to be "unique" and "slick." Given that description, the mystery tablet is nothing like the Samsung Galaxy Tab, which has a 7-inch screen (the iPad's is 10 inches) and no sliding keyboard.

Ballmer will show more slates from Dell and other manufacturers, according to the report. The devices will run Windows 7, though holding them in portrait mode with the keyboard sheathed will activate a "layered" interface. Similar to the announced BlackBerry PlayBook, the new machines are said to be aimed primarily at business users, an audience generally thought to be underserved by the iPad.

The Times report cited one source who suggested Microsoft could even show a tablet running Windows 8, though that appears unlikely. It's possible that Microsoft will show the devices running a variant of Windows 7 or Windows Phone 7 — one that's tailored to work with slate devices, similar to the tablet-specific version of Android dubbed "Honeycomb." Ballmer alluded to such a move in the summer when he said, "We're working with our hardware partners. We're tuning Windows 7 to new slate hardware designs that they're bringing them to market."

Microsoft is said to be encouraging manufacturers to write apps for the new slate machines in HTML5. The apps won't be sold in the Zune Marketplace or any other app store, the Times said. Instead, software partners will host the apps on their own websites.